Green Chemistry: A Promising Philosophy

Green Chemistry is the design of chemical products and processes that reduce or eliminate the use and generation of hazardous substances. It is an emerging philosophy which aims to protect environment by inventing new chemical processes that do not pollute. It is different and more fundamental than environmental chemistry which focuses on the study of pollutant chemicals and their effect on nature. Paul Anastas is considered to be the pioneer of green chemistry. During past two decades much work has been done to evolve green chemistry. Anastas and Warner developed the twelve principles of green chemistry as:

·         It is better to prevent waste than to treat or clean up waste after it is formed.

·         Synthetic methods should be designed to maximize the incorporation of all materials used in the process into the final product.

·         Wherever practicable, synthetic methodologies should be designed to use and generate substances that possess little or no toxicity to human health and the environment.

·         Chemical products should be designed to preserve efficacy of function while reducing toxicity.

·         The use of auxiliary substances (e.g. solvents, separation agents, etc.) should be made unnecessary wherever possible and, innocuous when used.

·         Energy requirements should be recognized for their environmental and economic impacts and should be minimized. Synthetic methods should be conducted at ambient temperature and pressure.

·         A raw material or feedstock should be renewable rather than depleting wherever technically and economically practicable.

·         Reduce derivatives - Unnecessary derivatization (blocking group, protection/ deprotection, temporary modification) should be avoided whenever possible.

·         Catalytic reagents (as selective as possible) are superior to stoichiometric reagents.

·         Chemical products should be designed so that at the end of their function they do not persist in the environment and break down into innocuous degradation products.

·         Analytical methodologies need to be further developed to allow for real-time, in-process monitoring and control prior to the formation of hazardous substances.

·         Substances and the form of a substance used in a chemical process should be chosen to minimize potential for chemical accidents, including releases, explosions, and fires.

Thus green chemistry or sustainable chemistry provides a technical solution to many environmental problems. It is effective due to design stage efforts, starting at the molecular level promotes designing out the hazardous properties and designing in environmentally appropriate features. The Noble prize for chemistry has been awarded for 2005 to Yves Chauvin, Robert Grubb and Richard Schrock. These chemists shared this prize for their contribution to the development of metathesis, an energetically favored and less hazardous method in organic synthesis. This has immense industrial applications. Besides its applications in the polymer chemistry (for making stronger plastics), metathesis has also found an important role in biotechnology in recent times. It represents a great step forward for “Green Chemistry” reducing potentially hazardous waste through smart chemistry. Green chemistry is now seen as a precursor to clean and green Pharma.

Education of Green Chemistry in India: There is a general consensus among educators for the incorporation of green chemistry into the chemistry and chemical engineering curricula. Green chemistry must permeate not only to the chemical industries, but it is necessary to bring about changes at the grass root level. This can be achieved by bringing about necessary changes in the chemistry curriculum not only in the college and university but also in the secondary school. The next generation of scientists needs to be trained in the methodologies, techniques and principles that are central to green chemistry. Taking a lead, Delhi University has established Green Chemistry Chapter of the American Chemical Society-Green Chemistry Institute. The Indian Green Chemistry Chapter has been doing Green Chemistry popularization, education and networking of green chemistry practitioners since a decade. Several national and international symposia and workshop have been organized on green chemistry, so that the principles of green chemistry can be instituted in the laboratory and the classroom and eventually in the industry. Green Chemistry Network Centre of Delhi University has initiated Green Chemistry and Industrial Green Chemistry awards recently. For Green Chemistry Education, a refresher course was organized for college teachers by the Centre for Professional Development in Higher Education in the University of Delhi. In India several colleges and universities have now started introducing courses in green chemistry at undergraduate and post graduate levels in various science disciplines. Department of Science and Technology (DST) has constituted a green chemistry task force. The task force of DST has developed a monograph on green chemistry laboratory experiments to complement the existing lab practices. DST also provides research fellowships in green chemistry and green process engineering. Government can do a lot of good for the cause of green chemistry by increasing public awareness and by bringing and enforcing strict environmental legislations.

Learning resources: For beginners the book ‘Green Chemistry: Theory and practice’ by Anastas and Warner is a must. A number of resources are available on the Internet to learn more about green chemistry:

http://en.wikipedia.org/wiki/Green_chemistry; EPA's Green Chemistry Program, http://www.epa.gov/greenchemistry; ACS's green chemistry website, http://www.chemistry.org/education/greenchem; the Green Chemistry Institute, http://www.lanl.gov/greenchemistry; and the Royal Society of Chemistry's Green Chemistry Network, http://www.chemsoc.org/networks/gcn/index.htm.